Pay-station automatic telephone system



June 10 1 924. 1

R. D. CONWAY -PAY5 TI9N AUTOMATIC TELEPHONE sYsf'aM Fi March 17. I *3Sheets-Sheet 1' hive/#02:. fiay Z7. Con wa y RmmeMm/ June 10, 1924.1,496,772

R. D. CQNWAY my 'STATIONAUTOMATIG fzysraonz sYsT-sm Filed March 17. 1923s Sheets-Sheet 5 Awe/#01 /7 0 y [7. Con way Patented June 10, 1924,

' OFFHCE.

ROY D. CONWAY, OF OHATHAM, NEW JERSEY, ASSIGNOR T0 WESTERN ELECTRICCOMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK;

PAY-STATION AUTOMATIC TELEPHONE SYSTEM.

Application filed March 17, 1921. Serial No. 452,977.

To all whom it may concern:

Be it known that I, ROY D. CONWAY, a citizen of the United States,residing at Chatham, in the county of Morris, State of New Jersey, haveinvented certain new and useful Improvements in Pay-Station AutomaticTelephone Systems, of which the following is a full, clear, concise, andexact description.

This invention relates to machine switching pay station telephonesystems.

The object of the invention 1s to provide an improved coin controlcircuit arrangement for automatic telephone systems of the type whereinthe calling party may either select another subscribers line or anoperators position. I

In the circuit arrangementof this invention, if the connection is builtup from one automatic station to another automatic station, the disposalof the coin which must be deposited in order to build up the connection,taken care of purely automatically upon the breaking down of theconnection, the coin box magnet being selectively operated by positiveor negative current from a coin control circuit at the central ofiice tocollect or refund the coin depending upon whether or not the calledparty has answered. hen, however, the calling party builds up aconnection to an operators position who then completes the connection,the coin control circuit is cut off and the coin is disposed of bycollect or refund current applied to the calling line by the operator.hen the operator removes the plug after disposing of the coin, theautomatic switches are released, but if she removes the plug withoutdisposing of the coin, the automatic switches are held set and thecalling lamp is again lighted to call her attention to this omission.

Referring to the drawings, Fig. 1 shows a calling line, a line switchand the coin control circuit; Fig. 2 shows a secondary line switch, afirst selector, a connector and an automatic station; Fig. 3 shows atrunk terminating at an operators position, and a cord circuit at suchposition and a manual station.

The invention will be most readily understood from a detaileddescription of'the operation of the system.

The removal of the receiver at substation A operates the line relay 100of the welllrnown Keith line switch PLS which closes the circuit of thepull down winding 101 to cause the line switch to plunge and seize thepreselected trunk 102, 103, as shown and described for example in-PatentNo. 1,304,369 of May 20, 1919 to A. J. Ray. The closure of contact 113of the primary line switch applies ground to holding conductor 114 leading to the pull down winding 200 of the secondary line switch SLScausing such switch to plunge and seize a preselected first selector FSin the well-known manner. This selector may be of the type shown inReissue Patent No. 13,901 issued April 13, 1915 to F. Newforth, J r. Theseizure of this selector causes a ground to be applied to the releasewire 201, 115 in the well-known manner.

These two line switches thus have extended the calling line to a firstselector. Relay L (Fig. 1) is now operated over the line circuit asfollows: free pole of battery, normal contact of relay H, resistance104, right armature and normal contact of relay NN, inner right armatureand normal contact of relay B, normal contact of relay A, trunkconductor 103, including a contact of the line switch, trunk conductor102 including a contact of the line switch, normal contact of relay A,inner left armature and normal contact of relay B, retardation coil 105,relay L, normal contact and outer left-hand armature of relay NN toground. If the coin has alreadybeen deposited in the coin box. contact109 is closed and a ground is applied through the polarized magnet 110to the calling line, but the resistance of magnet 110 prevents thisground from short-circuiting relay L which is in parallel with saidmagnet and the circuit characteristics are such that relay L operates.Relay L closes a circuit for relay DD to ground the release wire 107connected to the holding winding 108 of the lin switch before thecircuit of the pull down winding 101 is opened by the release of slowrelay 100 after such relay is cut off due to the line switch operating.The circuit for relay DD is as follows: battery left armature andalternate contact of relay L, normal contact of relay M, normal contactsof relays NN and D, relay DD to ground.

The lowermost armature of relay DD applies the ground referred to to thesleeve wire 107. Slowfrelay N also operates in parallel with relay DDand operates relay N N in a circuit including the inner left armatureand normal contact of relay IIH. Relay N N in attracting its outer leftarmature removes the shunt from around resistance 106 for a purposewhich will appear. In attracting its inner left armature it opens theoriginal circuit of relay DD andcloses a substitute circuit therefor tohold such relay energized to prevent premature release. Relay N appliesground to the sleeve wire 115. In attracting its right armature relayllN connects relay RT to the ring side R of the line in place ofresistance 104. Relay HT is marginal and its function is to test for thepresence of a coin in the coin box of the calling station A. This coinbox may be of the type shown in Patent No. 1,043,219, issued November 5,1912, to O. F. Forsberg. The deposit of the coin closed contact 109 toconnect the polarized magnet 110 to ground from the tip side of the lineas described. lVhen relay NN attracts its outer left armature, removingthe short circuit from about resistance 106 and attracts its rightarmature which substitutes the marginal test relay RT for the resistance104, the ground applied to the calling line at contact 109 by thedeposit of the coin causes the marginal coin test relay RT to operate toplace the central oflice stepping circuitunder control of the callingdial to permit the calling party to build up his connection. If the coinis not deposited the contact 109 is not closed and relay RT will notoperate, leaving the stepping circuit for th switches disabled. Thefunction :of resistance 106 is to prevent relay RT from operating if thecoin has not been deposited. This relay will operate only in casecontact 109 has grounded the line and will not operate through relay I1and resistance 106. The circuit would remain in this condition untileither the subscriber deposited a coin or restored his receiver whichlatter act would cause release of the equip-- ment. Relay ET inoperating energizes slow to operate relay S. this circuit including therelease wire now grounded at the front contact of relay N. In closingits co.n tact 116 relays locks up to the outer left an mature and normalcontact of relay Y. In

attracting its outermost left armature relay S, operates slow relay H,which locks itself in a circuit including the outer right arma-v tureand back contact of relay B, and also operates relay HI-I. Relay HH inattract ing its outer left armature extends the grounded spring 113 torelease wire 107 to hold the primary line switch set after relay DDreleases and removes the ground applied at the lowermost armature of therelay. In attracting its inner right armature relay 'HH applies a groundto the right of coil 105 in shunt of the relay L and resistance 106 toremove them from the impulse circuit asset/7s zvhich may be traced asfollows: free pole of battery, impulse relay R, innermost left armatureand front contact of relay S, inner right armature and normal contact ofrelay B, normal contact of relay A, the calling line circuit, normalcontact of relay A, retardation coil 105 to the ground referred to atthe inner right armature of relay Ill-l. Relay R closes a bridge to theimpulse relay of the first selector FS. This bridge leads from the tipconductor T, retardation coil 117, alternate contact of relay R, outerleft armature and normal contact of relay B, relay M, outer rightarmature and normal contact of relay Y to the ring conductor It.

Relay M operates in this bridge and closes a. holding circuit for slowrelay N, before its circuit has been opened by the dcenergization ofrelay L long enough for it to release, in order to prevent the circuitof relay A from being closed at this time. The seizure of the firstselector causes a ground to be placed on release wire 201, 115 in thewell-known manner.

The calling party now operates his sender 111 to interrupt the circuitof the impulse relay R. Relay R in turn repeats these impulses to theimpulse relay of the first selector FS which in the well-known mannerfinds an idle connector C which is then set on the called line multiplesand the called line is automatically rung. Vl hen the con nector wasseized slow relay 20st was operated by relay 203 to ground release wire206 in the well-known manner. The response of the called subscriberoperates relay 202 which reverses the direction of current flow in thecalling line supplied through relay 208. Polarized relay l? in the coincontrol circuit (Fig. 1) thereupon operates whereupon relay E operatesand locks up to the grounded conductor 10?. Relay E prepares a circuitfrom the collect source of positive current 118 which will be closed tocollect the coin upon the breaking down of the connection. Relays P andE operate relay .1, the circuit including the outer left armature, andalternate contact of relay E. the outer right armature, and alternatecontact of relay Relay A cuts off the bridge containing relay i whichreleases relay M, the latter releasing slow rela N. The callinglineisnow extended through to the connector relay 203. Talking current is fedto the called line through the windingsof relay 202 and to the callingline over a circuit including the free pole of battery, right winding ofrelay 203, outer armature and alternate contact of relay 202. the upperor tip talking conductor T to the calling line, returning over the loweror ring I conductor R, contact 120 of. relay E, polarized relay P-andits non-inductive shunt, the ring conductor R to ground through theinner armature and alternate contact of relay 202 and the left windingof relay 203. i

lWhen the calling party restores his receiver the connection isreleased, but the release of the primary line switch PLS is delayeduntil the coin control circuit of Fig. 1 has functioned to cause thecollection of the coin. WVhen the coin is collected this switch is alsoallowed to release.

When the calling party replaces his receiver, relay 203 releases,releasing the usual slow relay 204 which by energizing the releasemagnet 205 restores the connector. The retraction of the left armatureof slow relay 204. removes ground from the release wire 206 causing therelease relays (not shown) at the preceding selectors to deenergize torestore the corresponding selectors.

The relay S is at this time locked to this ground on the release wireand consequently releases when such ground is removed as described. Inretracting its intermediate left armature it opens the holding circuitof the secondary line switch SLS thus causing the release of the same inthe well-known manner. It will be remembered that when relay S firstoperated it operated relays H and Relay H then locked itself up in acircuit independent of relay S, including a back contact of rela B andheld relay HH operated. Relay H closed a local holding circuit for theprimary line switch including the holding winding 108 and contact 121 ofsuch switch, conductor 107, outer left armature and alternate contact ofrelay HH,c0I1 ductor 122 to grounded spring 113.

The relay S in retracting its outer left armature prepares a circuit fora pick up relay Y which is closed when the interrupting machine 123closes its upper contact. Relay Y then locks up to grounded conductor107. Relay Y in attracting its outer left armature prepares a circuitfor a coin current applying relay B which is closed when theinterrupting machine 123 next closes its lower contact. Relay B inoperating closes a circuit to apply collect current of positive polarityfrom the source 118 to the polarized magnet110 in the coin box, thiscircuit including the outer right armatures and alternate contactsofrelays E and Y, the winding of relay M. inner left armature andalternate contact of relay B, normal contact of relay A and the tip sideof the line to ground through the coin box magnet 110. Relay A wasreleased when relay S released. The coin box magnet 110 in operating onpositive current causes the collection of the coin and the opening ofcontact 109 as described in said Forsberg patent. When relay B operatesfrom the interrupting machine 123 as described it opens at its outerright armature the locking circuit of slow relay H which is holdingrelay ,HH operated. The latter relay is maintaining the holding circuitof the line switch closed as described. Before the slow r lay H candeenergize when its locking circuit is opened by relay B another circuitfor relay H is closed at the front contact of relay'M in the coincurrent circuit operated due to relay B operating. When relay B isreleased by the interrupting machine it again closes the'locking circuitfor slow relay H. If the coin is collected by the first impulse the coinground is removed from the line by the opening of contact 109 and thenext time the relay B is operated by the interrupting machine and opensthe locking circuit of slow relay H, the other circuit for this relay isnot closed since relay M does not operate due to the absence of the coinground on the tip side of the line. Consequently the slow relay Hreleases, releasing relay HH which-in retracting its outer left armatureopens the holding circuit described for the primary line switch whichreleases in the well-known manner. Relays E and Y release due to therelease of relay HH.

If the called line is busy or the called subscriber fails to answer thepolarized relay P would not operate and lock relay E. Upon the operationof relay Y therefore due to the release of relay S when the callingparty replaces his receiver, relay Y would connect refund current ofnegative polarity from the source 119 by way of the outer right armatureand back contact of relay E to the call-- ing line, instead of collectcurrent, and the coin would be refunded.

A lamp 125 controlled by relay Y is provided to give a signal by itssustained illumination in case of trouble.

Assuming now that the calling party desired a connection to an operatorsposition. In that case he inserts a coin and dials a certain digit ordigits to select a trunk 207, 208, 209 terminating in a. jack 300 at anoperators position.

These trunks are shown as terminating in a level of the first selectorFS but they may terminate in any selector. \Vhen the trunk 207 208, 209is seized, relay 301 operates in a circuit including its grounded rightwind-- ing, outer left normal contact of relay 302, right normal contactof relay 303, left wind ing of relay 301, inner left normal contact ofrelay 303 over the tip conductor, retardation coil 117, alternatecontact of impulse relay R, relay M, ring side of the line, conductor 301 to battery at the middle left armature of relay 303.

the outer right armature and alternate contact of relay S,-and .outerleft normal contact of relay E. Relay A cuts off the repeater andconnects the calling line through to the tip and ring contacts of theack 300, relay E not being operated at this time due to the failure ofpolarized relay P to operate. Thus relay P is excluded from the callingline circuit. When relay 303 operated, it applied ground from thecontact 305 of relay 302 to the sleeve or release wire 306 to hold upthe release relays (not shown) at the preceding sclectors and the relayS in the coin control circuit just as when the connector C was seized.

' The seizure of the trunk caused a tone to be transmitted frominduction coil 309 to the calling line to inform the subscriber that thecall is extended to the jack 300, this cincuit including the innernormal contacts of relay 310. The attraction of the middle left armatureof relay 303 closed the circuit of the calling lamp 307. The operatornow inserts plug 308 into jack 300 but the current flow from the batteryin the cord to the calling line is not in the proper direction tooperate polarized relay P and therefore relay E remains inert. When theoperator inserts plug 303 into ack 300 relay 302 operates, and byclosing its inner right contact short circuits the primary winding ofinduction coil 309, thus removing the tone from the calling line. Classof service tone current from the source 197 associated with the callingline now flows through the primary winding of induction coil 309 toground at the inner right armature of relay 302, this tone currenthaving been shert circuited at contact 305 up to this time. By inductionthrough the secondary winding of coil 309 this tone is transmitted tothe operators head set when she actuates her listening key 312. Theoperator now actuates key 313 which operates relay 310 the circuitincluding-the middle left armature and alternate contact of relay 303, acontact of key 313, the tip side of the line to the grounded side of thebattery in the cord. In attracting its outer right armature it locksitself so that-it remains energized after key 313 is released. Whilerelay 310 by attracting its inner armatures opens the original classtone circuit to the operators head set, a substitute circuit fortransmitting the tone is closed including the confacts of key 313, andthus this tone is not removed until the key is released. Thus theoperator can reapply the tone at any time while the plug is inserted bymerely operating key The operator now talks with the calling party,learns the number desired, and if a charge is-required instructs him asto the coins to be deposited. As the coins drop into the box they strikegongs which transmit tones to inform the operator of theirdenominations. The operator then neacym tests the called line jack inthe well-known manner, and if idle, inserts the plug and rings over theline. When the called party answers, or at any time thereafter, sheactuates collect key 31 1-. current from the source of positive current315 over both sides of the trunk and calling line in parallel to groundthrough the polarized magnet 110 in thecoin box to collect the coins.cuit to light lamp 317, and as soon as the key is released the coin boxmagnet 110 releases and disconnects the coin ground. She again acrnatcsthe key and if the lamp does not light it indicates that the coin boxmagnet has functioned properly and removed the coin ground.

ll hen the calling and called parties replace their receivers thesupervisory relays 348, 339 release lighting the, lamps 320, 331 in thewell'known manner whereupon the operator removes the plugs. The removalof plug 308 from jack 300 releases relay 302 which in closing its outerleft back contact shunts the right winding of relay 30.1, the relay 310being still locked up. Belay 301 thereupon releases releasing relay 303.Relay 303 in releasing its middle left armature releases relay 310, andin retracting its outer left armature removes ground from the releasewire 306 causing the release of the selectors and relay S, Fig. 1. RelayS in retracting its intermediate left armature releases the secondaryline switch and .in retracting its outer left armature opens theoriginal circuit of slow relay H. This relay is however locked in acircuit including the outer right normal contact of relay B. Relay Yoperated and locked when relay S released as described and connected theinterrupting machine to relay B. When therefore this machine operatesrelay B and opens this locking circuit, no coin ground being present atthe substation, relay M fails to operate and no alternative circuit isclosed for relay H whereupon it releases as described, releasing relayHH. Relay HH in retracting its outer left armature opens the holdingcircuit for the primary line switch causing its release.

If the coins for any reason were to be refunded the operator wouldactuate refund key 318 instead of collect key 314, which causes refundcurrentof negative polarity to be impressed on the calling line from thecurrent source 319 through relay 330 to operate the polarized relay 110to refund the coins. Lamp 321 lights upon the second actuation of thekey, if the coin box magnet has not operated properly and removed thecoin ground.

If the operator removes the plug 308 without actuating either coin keythe connection is not released but the calling lamp This impressescollect The relay 316 operates in this cir- J.)

307 is again lighted in the following manner to call her attention tothis omission. If she has failed to dispose of the coin when the plug isremoved ground is present in the tip side of the line from the coin boxand this ground completes a circuit over conductor 322, inner rightarmature and front contact of relay 310, inner left armature and backcontact of relay 302, right armature and front contact of relay 303,left winding of relay 301, innermost left armature and front cont-actofrelay 303 to battery. This holds relay 301 which. in turn holds relay303, the latter holding relay 310. Relay 303 applies battery to lamp 307over the outer right armature and normal contact of relay 302 whichreleased when the plug was pulled out. Relay 303 in maintaining itsoutermost left armature attracted holds ground on release wire 306 thuspreventing the release of the switches. The operator inserts the plugand disposes of the coin, thus removing the coin ground. Upon theremoval of the plug the connection is released as described.

Certain lines called free lines are segregated upon connectors which donot reverse the current flow upon the response of the called party. On acall to such a line the relay A is not operated due to relay P notoperating and current is fed to the calling line over the relay R andnormal contacts of relay A, the circuit being balanced by a retardationcoil 105. The retardation coil 117 in a call of this character preventsshunting of the voice currents. Upon the replacement of the receiver bythe calling party the connection is broken down and due to the relay Ebeing in normal condition, the coin control circuit functions to refundthe coin exactly as described when the called line was busy.

The discharge of the condensers is prevented from interfering with thecharacter of the impulses transmitted by the impulse relay R to theswitches in the following manner. When the relay R is energized due tothe deposit of the coinit operates relay D. Relay D operates relay DD.Relay DD connects the condensers to the tip and ring conductors.However, upon the first break in the calling line circuit by the dialrelay D releases quickly, releasing relay DD which disconnectsthecondensers from outgoing trunk conductors. Relay D is slow to operateas shown and remains inert during the time the armature of relay R isvibrating and only energizes again when the 7 line circuit is closed asthe dial reaches its normal position. These condensers are provided toinductively connect the calling and called ends in the case of freecalls.

"to preventit from attracting its armatures Relay S is made slow tooperate, as shown,

and locking due to possible momentary operation of marginal coin testrelay RT under certain conditions at the time it is connected to thering side of the line in;

and

to selectively operate the coin box magnet to dispose of the coin, meansactuated by the disconnection of the connecting circuit from the trunkfor releasing the automatic switches, and means for preventing therelease of said switches and for again actuating said signal if theoperator disconnects the connecting circuit from the trunk withoutdisposing of the coin.

' 2. In a telephone system, the combination with subscribers lines, coinboxes associated therewith having polarized magnets therein,

an operators position, trunks terminating thereat in jacks, automaticswitches for extending the calling line to one of said trunks, a callinglamp for said trunk lighted by the seizure thereof, a cord circuit,means actuated by the insertion of the answering plug of the cordcircuit into the jack of theseized trunk for extinguishingv said lamp,sources of positive and negative current, .keys in said cord circuit forapplying currenttothe calling line to selectively operate the coin boXmagnet to collect or refund the coin, means actuated by thewithdrawal-of the plug from the jack for releasing the automaticswitches, and means for preventingthe release of said switches and foragain lighting the calling lamp actuated if the plug is withdrawn beforethe coin is collected or re funded.

3. In a telephone system, the combination with subscribers lines, coinboxes associated therewith, senders for said lines, automatic numericaland non-numerical switches, operators positions, means actuated by thedeposit of a coin for altering the substation coin-box connections,means controlled by the removal of the receiver and the altered coin boxconnection for placing said sender in operative relation with saidnumerical switches whereby the subscriber may select a position, acalling lamp lighted thereby, means controlled by the operator foranswering the call, means controlled by the operator for collecting orrefunding the coin and restoring to normal condition the coin *boxconnections, and means for preventin the use line,

release of the switches and for again lighting the lamp if the operatordisconnects the calling line from her position without restoring tonormal condition the coin box. connections. Q

45. In a telephone system, the combination with subscribers lines, coinboxes connected therewith, senders for said lines, automaticnon-numerical and numerical switches, op erators positions, meansactuated by the tie posit of a coin for grounding one side of the meansjointly controlled by said grounded condition and the removal of thereceiver for placing said sender in operative relation with saidnumerical switches whereby the subscriber may select a position, .1calling lamp lighted thereby, means controlled by the operator foranswering the call and extinguishing the lamp, means coir trolled by theoperator for collecting or re funding the coin and removing said ground,means actuated by the disconnection of the calling line from theposition by the operator for releasing the switches, and means actuatedby the presence of said ground when the operator disconnects forpreventing the re lease of the switches and again lighting the callinglamp.

5. In a telephone system, the combination with subscribers lines, coinboxes associated therewith, senders for said lines, automatic switchescontrolled thereby for interconnecting a pair of lines, a coin controlcircuit at the central ofiice for applying collect or refund current tothe calling line automatically to collect or refund a coin upon thebreaking down of the connection dependent upon whether or not the calledparty has an swered, an operators position adapted to be selected bysaid automatic switches under control of the sender, a calling lamplighted thereby, meanscontrolled by the selection of said position forrendering said coin control circuit inefiective, and manual meanscontrolled by the operator for collecting or refunding the coin.

6. In a telephone system, the combination with subscribers lines, coinboxes associated therewith, senders with said lines, automatic switchescontrolled thereby for interconnect ing a pair of lines, a coin controlcircuit at the central ofiice for applying collect or re fundcurrenttothe calling line automatically to collect or refund a coin uponthe breaking down of the connection dependent upon whether or not thecalled party has answered, an operators position adapted tobe selectedby said automatic switches under control ofthe sender, a calling lamplighted thereby, means controlled by the selection of said position forrendering said coin control circuit J ineffective, manual meanscontrolled by the operator for collecting or re funding the coin, andmeans actuated if the operator disconnects without disposing of acey/athe coin for holding the connection to her position and again lightingthe calling lamp.

'7. In a telephone system, the combination with subscribers lines, coinboxes associated therewith, senders for said lines, automatic selectorsand. connectors for interconnecting said lines, a coin control circuitbefore the first of said selectors for applying collect or re fundcurrent to the calling line automatically upon the breaking down of theconnection dependent upon whether or not the called arty has answered, arepeating relay bridge associated with said coin control circuitactuated by the sender to repeat impulses to said automatic switches toset the same, an operators position selectabl by one of said selectors,means controlled by the selection of the position for cutting off saidcoin control circuit and said bridge and for cutting the calling linedirectly through'to the position, and keys controlled by the operatorfor applyi collect or refund current to the ailing line. I v

8; In a telephone system, the combination with subscribers lines,coin'boxes associated therewith, sendersforsaid lines, a repeating relaybridge at the central o'flice, means con-- trolled by the deposit of acoin for placing the sender in operative relation to said relay wherebythe subscriber may build up a connection, a coin control circuit beforethe first of said selectors for applying collect or refund current tothe calling line automatically upon the breaking down of the connectiondependent upon whether or not the called party has answered, anoperators position, means controlled by the selection of the positionfor cutting off said coin control. circuit and said bridge and forcutting the calling line directly through to the position, a callinglamp lighted thereby; keys controlled by the operator for applyingcollect or refund currentto the calling line to operate the coin boxmagnet to dispose of the coin, and means for preventing the release ofthe connection and for again lighting the lamp if the operatordisconnects without disposing of t-hecoin.

9. In a telephone system, the combination with subscribers lines, coinboxes associated therewith, senders for said lines, a. repeating relaybridge at the central office, means controlled by the deposit of a coinfor placing the sender in operative relation with the relay of saidbridge whereby the subscriber may build up a connection, an. operatorsposition, means controlled .by the selection of the position for cuttingoff said coin control circuit and said bridge and for cutting thecalling line directly through to the position, a calling lamp lightedthereby, keys controlled by the operator for applying collect or refundcurrent to the calling line to operate the coin box :magnet to disposeof the coin, and means for preventing the release of the connection andfor again lighting the lamp if the operator disconnects withoutdisposing of the coin.

10. In a telephone system, the combination with subscribers lines, coinboxes associated therewith senders for said lines, automatic numericaland non-numerical. switches, for interconnecting a pair of lines, a coincontrol circuit at the central office for applying collect or refundcurrent to the calling line, means actuated by the replacement of thereceiver by the calling subscriber for holding the connection to thecoin control circuit and releasing the numerical switches and forcausing said coin control circuit to apply collect or refund current tothe calling line depending upon whether or not the called party hasanswered, an operators position adapted to be selected by said automaticswitches, a calling lamp lighted thereby, means controlled by theselection of said position for rendering said coin control circuitineffective, and manual means controlled by-the operator for collectingor refunding the coin.

11. In a telephone system, the combination with subscribers lines, coinboxes associated therewith, senders for said lines, primary andsecondary line switches and numerical switches for interconnecting apair of lines, a coin control circuit at the central oflice for applyingcollect or refund current to the calling line, said coin control circuitbeing located between said non-numerical switches, means actuated by thereplacement of the receiver by the calling subscriber for holding theconnection to the coin control circuit and releasing the secondary lineswitch and numerical switches and for causing said coin control circuitto apply collect or refund current to the calling line depending uponwhether or not the called party has answered, an operators positionadapted to be selected by said automatic switches, a calling lamplighted thereby, means controlled'by the selection of said position forrendering said coin control circuit inefl'ective, manual meanscontrolled by the operator for collecting or refunding the coin, andmeans actuated if the operator disconnects without disposing of the coinfor holding the connection to her position and again lighting thecalling lamp.

In witness whereof I hereunto subscribe my name this 14 day of March, A.D., 1921.

ROY D. CONWAY.

